Update: Hubble on hold until February

NASA's fifth and final Hubble Space Telescope servicing mission isn't likely to fly before mid-February and could be grounded until next spring so that a critical spare computer can be launched to the observatory, officials said today.

"We've more or less made that decision," NASA science chief Ed Weiler told reporters in a teleconference this evening.

"If we are going to do this final servicing mission and spend the money involved and launch seven astronauts, we thought it would be proper due diligence if we assured that this mission would leave Hubble with a good solid five- or six- or seven-year future."

NASA was aiming to launch Atlantis and seven astronauts on a Hubble servicing mission on Oct. 14, but those plans were dashed when a critical computer failed over the weekend. The failure forced NASA to temporarily shut down science observations until a back-up could be pressed into service.

NASA flight controllers are taking a cautious approach to turning on the back-up unit because it has never been used in space. The prime unit has been operating since the telescope was launched in 1990.

The computer in question is called a Control Unit/Science Data Formatter. It formats and sends commands to the observatory's main flight control computer as well as its science instruments, and science observations cannot be carried out unless it is operating properly.

NASA expects to switch to the back-up unit and restore science observations within the next two weeks. But the telescope still would be vulnerable to single failures. If the back-up unit or any of five linked electronics components failed, then the telescope would be rendered useless.

"If we lose those then the game is over," NASA Hubble Program Manager Preston Burch said.

Weiler said the failure could be the proverbial blessing in disguise.

"There have been a lot of ups and downs on Hubble. But one way to look at this is it was not necessarily a knuckleball. It was a high hard one we maybe will be able to hit over the fence," he said.

"I mean, think about the other option. Think about if this failure had happened two weeks after the servicing mission. We would have just put two new instruments in and thought we had extended the life for five or 10 years, and this thing failed after the last shuttle mission to Hubble," Weiler added.

"We could have lost the mission in six, 12 or 18 months. So in some sense, if this had to happen, it couldn't have happened at a better time."

NASA decided to delay the mission until a ground testing unit can be qualified for flight. That process is expected to take a couple of months. Burch said the earliest the spare could be delivered to Kennedy Space Center likely is early January. A mid-February launch is the earliest one he could envision.

So NASA is aiming to proceed with the planned Nov. 16 launch of Endeavour on an International Space Station outfitting mission. Shuttle progam managers are looking at moving that launch up to Nov. 14.

NASA is facing a Nov. 25 deadline to get the mission aloft. The sun angle on the station between Nov. 26 and Dec. 17 will be such that the station will not be able to generate enough electrical power or dispel enough heat to accomodate a docked shuttle orbiter.

Shuttle Discovery now is slated to launch in mid-February on a mission to haul up the fourth and final set of massive American solar wings to the station, and the Russians plan a crew rotation mission to the outpost next April. The sun angle on the station also will be a problem next May. So NASA might opt to proceed with the Discovery mission in February and then launch the Hubble mission in the spring.

NASA Shuttle Program Manager John Shannon said the Atlantis astronauts, who survived Hurricane Ike earlier this month and now face a lengthy delay, took the news in stride.

"This is just one of those things that comes with spaceflight, and I think the crew is very stoic," he said. "And they will be ready to go fly when the hardware is ready to go fly."

Weiler tried to put the problem in perspective. He said it is nowhere near as serious as the post-launch discovery that the telescope's primary mirror had been ground to the wrong prescription.

The spherical abberation rendered Hubble nearsighted, and the project became a national joke until the myopia was corrected during a make-or-break repair mission in December 1993.

"This is nothing compared to spherical aberattion. I mean, this whole program was declared dead in 1990 -- it would never survive it. Not only did we survive it, but we came out as the Great American Comeback story," Weiler said.

"Hubble has a habit of coming back from adversity, and the Hubble team -- which includes the shuttle team -- works miracles. And you know, I'm not too concerned about this," Weiler said. "We'll find a way to get this fixed."

NOTE ON IMAGES: Click to enlarge and save the awesome photos of the Hubble Space Telescope taken by the crew of the STS-103 mission in December 1999. Then click the enlarged images for even larger views.